Router A :
ip route 192.168.3.0 255.255.255.0 192.168.2.2
^ ^ ^
network mask gateway
ip route 192.168.3.0 255.255.255.0 192.168.1.1
^ ^ ^
network mask gateway
Router B :
vice versa to Router A
References :
http://serverfault.com/questions/171551/help-me-understand-the-ip-route-command-for-cisco-routers